LABORATORY STUDY ON PERMEABILIY OF DIFFERENT SUBBASE AND BASE COURSES

Abstract

Highway Personnel's believe that excess water is the primary cause of premature failure of the pavement. Roads have been designed in India for specific years of design life. National authorities spend ample amount of money in India for the construction and maintenance of roads. A major portion of effort results in vain if water deteriorates the pavement layers on account of improper drainage thereby decreasing the service life. Permeability is one of the basic criteria for drainage design for drainage design of various pavement materials. It is necessary that various pavement materials particularly used in base and sub base course should be protected from detrimental effects of water. So, therefore, it is necessary to evaluate the coefficient of permeability for various pavement materials. Some waste products, eg. Flyash can be utilized as an additive to conventional construction materials. Flyash is available enormously and almost free of cost. Subbase course can be constructed using pond ash or bottom ash replacing conventional material. The main concern is to evaluate the coefficient of permeability, CBR% for GSB, WMM with or without mixing flyash so as to analyze the variation in k value. An attempt has been made to inculcate the use of fiber as an additive to local soil and flyash. Fiber reinforced soil cum flyash combination resulted in successful attainment of k value within the range of 0.4-2cm/sec.